Method of handling and protecting harvested tobacco leaves from radiosotope contamination



United States Patent 3,403,687 METHOD OF HANDLING AND PROTECTING HARVESTED TOBACCO LEAVES FROM RA- DIOISOTOPE CONTAMINATION Wilhelm Kahane, 20 W. 72nd St., New York, N. 10023, and Magdalena Efros and Norbert Efros, New York, N.Y. (both of 597 Beech St., Haworth, NJ. 07641) No Drawing. Filed Jan. 10, 1966, Ser. No. 519,409 2 Claims. (Cl. 131-140) ABSTRACT OF THE DISCLOSURE The method of preventing the contamination of tobacco by radioisotopes by packing and maintaining tobacco leaves in air-tight sealed containers, preferably made of plastic film bags, during the operations of transportation and storage of said leaves. The packing is done before treating, between phases of that treating, and after completion of the treating and from harvest of the tobacco leaves until their actual use in the manufacture of the following smoking articles: cigarettes, cigars and pipe to- 'bacco.

This invention covers a method for an improvement of the-value of tobacco from the point of view of the relation between cigarette smoking and health. The proposed method is intended to be used in conjunction with tobacco treating processes employing recirculation of the same mass of air within the space housing these processes to prevent or at least to minimize the increases, after harvest, of tobacco leaves content in those natural radiosotopes which are susceptible to be transferred into the smoke of cigarettes.

It has been known for many years, in the pursuit of the possible initiators of cigarette smokers lung cancer, that plants, hence also tobacco, contain the alpha-emitting radio element polonium-21O (radium F) accompanied by its parent and support lead-210 (radium D), and that at least part of that content comes from the decay of the airs radon. It has been also known for many years that the atmospheric air is being contaminated with the gaseous radio elements radon, thoron and actinon, incessantly received mostly from the soil, plants, dust and buildings. It has been known for a long time that said gaseous elements, through radioactive decay, are a source of the radioisotopes of atomic number Z equal or lower than 84 of the three families of naturally-occurring radio elements: the uranium-radium, the thorium, and the actino-uranium series. Sealed plastic bags have been used extensively in the food industry for many years. But in spite of all that knowledge, no thought was given as yet to the advisability of using airtight sealed containers to minimize the increases in tobacco leaves, between harvest and the time of use, of their initial content in the above mentioned radioisotopes by the amounts generated through decay of the radon, thoron and actinon of the air. Human food of agricultural origin has, in general, about the same level of radioactivity as tobacco, and that level, too, increases from harvest to consumption, following decay of the same gaseous radioelements of the air. But while the foods natural radioactivity is fully eliminated as a result of the human bodys functions and defenses developed by Nature to cope with natural dangers, elimination of the tobacco smokes radioactivity is impaired by the known inhibitory action of tobacco smoke, a man-made danger, upon the bronchial tree cilias mobility. For this reason, we believe it advisable to use means aiming at preventing the increase in radioactivity in tobacco leaves while no such action is needed for food.

The transfer of polonium-210 (Z=84) from tobacco ice into the cigarette smoke was explained by that elements complete volatility above 500 C. We are, however, of the opinion that, because of the large excess of air in the tobaccos combustion zone, the transfer of metallic constituents from tobacco into its smoke is not related to the pure elements volatility but only to that of its oxide. As the oxides of the isotopes of all three families of the natural radioelements whose atomic number Z is higher than 84 are refractory compounds melting much above the tobaccos combustion temperature, no naturalradioelement with Z higher than 84 can be found in a tobacco smoke. Then, we shall further remove as well the possibility of the presence in the smoke, in relatively appreciable amounts, of all radio elements with Z equal or lower than 84, because of their half-lives being too short and therefore their amounts too low, with the exception of the following isotopes which have half-lives longer than one day:

The above listed three daughters of radon are, thus, practically the only natural radio elements liable to pass from the tobacco into its smoke. The fact that the melting or sublimation points of the oxides of all these three elements are in the range of cigarette combustion temperatures, but somewhat above those in cigars and much above of those in pipes, explains the findings of the epidemiological statistics on smoking and health that cigarettesmokers have a much higher mortality risk from lung cancer than cigaror pipe-smokers.

The object of our invention is to improve the technique of handling the tobacco leaves during the time elapsed between harvest and their use in a cigarette plant, so that the leaves content in those three radio elements daughters of radon, be permitted to remain practically at the same level as at time of harvest. That object is achieved in this invention by preventing the atmosphere around the leaves from receiving fresh amounts of radon during their transportation and storage, i.e. throughout those periods, between harvest and the actual use of the tobacco leaves in the manufacture of smoking articles, when there is no need for refreshing the gaseous atmosphere about the leaves. To this effect, essentially the same mass of air is kept in the containers housing the leaves in storage or transportation. The correct use of this invention requires that in spaces housing tobacco treating operations that need refreshing of the atmosphere about the leaves, the same air may be recirculated and reconditioned--with the aid of the well known methods-for approximate maintenance of the composition desired for the specific operation and for the health of the personnel, with admission only of the extremely small amounts of fresh air as required by said reconditioning. Of course, the floor and walls of said spaces shall be made air-tight and of materials impervious to gases.

In those curing processes which use fuel smoke in contact with the tobacco leaves, as in fire-curing and in some types of flue-curing, and because radon-contaminated atmospheric air is used to produce that smoke, the same smoke shall be recirculated and only a minimum admission of fresh smoke will be admitted as a reconditioning operation of space atmosphere.

The containers, such as barrels, boxes and bags, serving in the transportation or storage of leaves shall be airtight. The use of sealed bags made of plastic film is a convenient solution.

What we claim as new is: *1. A method of handling and protecting harvested leaves of tobacco from radioi'sotopes which, after treating, are actually used in the manufacture of the following smoking articles: cigarettes, cigars and pipe tobacco;

this method consisting in the step of packing and keeping said tobacco leaves in air-tight sealed radioisotope excluding containers during the operations of transportation and storage of said leaves before their treating, between phase of that treating, and after completion of the treating, until the actual use of said leaves in the manufacture of the above listed smoking articles; the above described method being for the handling only of those tobacco leaves which are actually used in the manufacture of said smoking articles. 2. A method as claimed in. claim 1, the therein mentioned containers being air-tight sealed plastic film bags.

4 References Cited UNITED STATES PATENTS 3,202,157 8/1965 Touton 131-14O X 3,233,339 2/1966 Long et a] 131140 X 3,327,716 6/1967 Kohan 13114O X OTHER REFERENCES Agr. Engr, A Forced-Ventilation Tobacco Curing System, July 1952, pp. 429-430.

Science, Radium-226 and Polonium-ZIO, in Leaf Tobacco and Tobacco Soil, November 1964, pp. 1043-1045.

Tobacco, Compartmental Bulk Curing Facilities for Tobacco Research, Aug. 28, 1964, pp. 33-38.

Tobacco, Radium-226 and Polonium-210 in Burley and Cigar Wrapper Tobacco, Aug. 19, 1966, pp. 28-29.

ALDRICH F. MEDBERY, Primary Examiner. 

